Franz joseph weiss



(No Model.)

. P. J. WEISS.

Y AIR PUMP.

No. 307,363. I Patented Oct. 28, 18,84.

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FRANZ JOSEPH WEISS, OF BASLE, SWITZERLAND.

AIR-PUMP.

SPECIFICATION forming part of Letters Patent No. 307,363, dated October 28,1884.

Application filed August 17, 1882. (,No mode-l.) Patented in Germany June 2, 1882, No. 21,253,- 'in England July 26, 1882, No. 3,551,- in Belgium August 16, 1882, No. 58,588, and in France October 30, 1882, No. 150,319.

T0 at whom, it may concern Be it known that I, FRANZ Josnrrr Wnrss, a citizen of the Republic of Switzerland, residing in the city and canton of Basle, and Republic of Switzerland, have invented anew and useful Improvement in Air-Pumps, whichimprovement is fully set forth in the following specification, reference being had to the accompanying drawings, in which- My invention relates to pumps adapted for the compression or rarefaction of air or gases; The practical operation of pumps of this character, as heretofore constructed, have been de fective, in as much as they are only operative up to a certain limit. In compressionpumps this limit is reached when the density of air in the reservoir prevents the opening of the induction-valves-that is, when the air in the reservoir is under a pressure equal to that which can be attained by a single stroke of the pistonand in exhaust-pumps the limit is reached when a stroke of the piston does not produce a greater rarefaction ofthe air under atmospheric pressure contained in the clearance space of the pump-cylinder than has been produced in the receptacle from which the air is being exhaust'ed.

Heretofore it has been proposed to relieve the pressure upon the induction-valves of compression-pumps by causing a current of air or other fluid to move away from said valve just at the time the compressingpiston commenced its stroke; but this involved the construction of a complicated and expensive pump, and was not applicable to pumps for the rarefaction of air or gases, because there was no reduction in the pressure of air under atmospheric pressure contained in the clearancespace of the cylinder.

The object of my invention is to extend the limit of operation of pumps of this class; and to this end my invention consists in the method of rarefying or reducing the pressure of the atmospheric air contained in. the clearance-space of the pump-cylinder while the piston is at its dead-point.

I prefer to explain the principle of my in; vention in connection with an apparatus designed for the rarefaction of air or gases; but it will be readily understood by those skilled in the art how these principles can be applied in apparatus designed for compression.

In the accompanying drawings, Figure 1 illustrates two single-acting pumps arranged to carry out my invention. Fig. 2 represents adouble-actingpump embodying my improvement.

I11 Fig. 1 of the drawings, A represents a vacuum apparatus or a receptacle from which the air or gas is to be exhausted. This apparatus is suitably connected with both of the pump-cylinders, A and A arranged side by side, as shown, and respectively provided with pistons a (6 the rods of which are connected to the opposite ends of a lever, G, fulcrnmed at its center in a standard, 0, supported between the cylinders. The leverC is actuated by any suitable means to give the pistons an equal and simultaneous traverse in opposite directions. The cylinders and pistons are provided with upwardlyopeningvalves, as shown. The cylinders are connected at a point below the limit of stroke of the pistons (the clearance space) by means of a pipe, I), of small diameter, and this pipe is normally closed by a valve, a, which is designed to'be opened only while the pistons are at the dead-p oint, or, in other words, during the momentary interval between the ending of one stroke and the commencement of the next. I have shown this valve to as provided with a hand-wheel, so that it may be operated at the proper times by an attendant; but it will be obvious to those familiar with mechanics that this valve may be arranged to be operated automatically by the lever O or other moving parts of the device.

In operation the action of the pump arranged to carry out my invention will be as follows: We will suppose the pistons are in the position shown in the drawings, having just completed a stroke. Under this condition of affairs the air in the suction-space of cylinder A will be under a pressurelower or less than atmospheric pressure, and equal, or nearly so, to that in the vacuum apparatus, and that in the clearancespace of cylinder A will be at atmospheric pressure. Should the piston a now commence a stroke, no air could be drawn or exhausted from the vacuum apparatus A until the air in the clearance-space was rarefied to a degree equaling that of the air contained in said apparatussay, for instance, when the piston co has completed a halfstrokeso that this piston would only be operative for rarefaction during half of its stroke; but if, on the other hand, the valve a in pipe I b were momentarily opened before the commencement of the stroke, the air in the clearance-space in cylinder A would expand into the suction-space of cylinder A thus equalizin g the pressure in said cylinders and reducing the pressure in said clearance-space below atmospheric pressure, so that, say, a quarterstroke of piston a would reduce the pressure in the clearancespace to a degree equaling that in the vacuum apparatus, thus rendering said piston operative for the exhaustion of air from said apparatus during three-quarters of its stroke.

In Fig. 2 I have illustrated a double-acting pump, adapted to operate on the same principles as the two single pumps hereinbefore described. A pump-cylinder, B, open at both ends, is supported within a casing, D, communicating with the vacuum apparatus (not shown) by means of a pipe, d. The openings between the cylinder 13 and its casing D are normally closed by automaticallyoperating valves E e and E e. The piston B is represented as making an up-stroke, hereby drawing air through valve E, and discharging it through valve 6. The ends of the casing D are connected by the narrow pipe b, which is normally closed by the cook a. As the operation of this pump will be apparent to those skilled in the art, further explanation is here deemed unnecessary. As the air in the suction-space is at the same pressure, or nearly so, as that contained in the vacuum apparatus, it follows that the same result could be attainedthat is, the reduction of pressure of the air in the clearance-spaceby connecting said space with the vacuum apparatus by means of pipe 12, instead of with the suction-space. In this way one of ,the pumps in Fig. 1 might be dispensed with taining valved pistons a a", and connected by a pipe, I), having avalve, a, with said cylinders, and by a valved pipe to a vacuum apparatus, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

FRANZ JOSEPH WVEISS.

Witnesses:

HENRY HOFACKER, A. BURCKHARDT. 

